Field of the Invention
The present invention relates to a disc-shaped grindstone which is used to grind, for example, a shaft object such as a crank shaft.
Description of the Related Art
Hitherto, there is known a disc-shaped grindstone used to grind a pin portion and a journal portion of a crank shaft (for example, see Japanese Patent Publication No. 11-207576 A). The disc-shaped grindstone grinds a shaft object such as a crank shaft by the outer circumferential surface thereof in a rotation state.